MX2014011288A

MX2014011288A - Sorting apparatus for arthropods and method of use thereof.

Info

Publication number: MX2014011288A
Application number: MX2014011288A
Authority: MX
Inventors: Luke Alphey; Derric David Nimmo
Original assignee: Oxitec Ltd
Priority date: 2012-03-20
Filing date: 2013-03-20
Publication date: 2015-01-12
Also published as: US9180464B2; MX359675B; AU2013237162B2; US20150008163A1; GB201204860D0; AR090447A1; GB2503411B; BR112014023285A2; AU2013237162A1; SG10201609806YA; SG11201405906QA; MY166885A; WO2013140167A1; GB2503411A; IN2014DN08130A

Abstract

There is provided an apparatus for sorting arthropod larvae and pupae and in particular, although not necessarily, to sorting arthropod pupae on the basis of size, especially in mosquitoes. The apparatus comprises two parallel bars (14) pivotally mounted in a frame such that the distance between the bars is adjustable. Insect larvae and pupae may be inserted into a chamber with one side formed by the grid of bars and inserted into water to separate the different forms.

Description

CLASSIFIER APPARATUS FOR ARTHROPODS AND METHODS USE OF THE SAME TECHNICAL FIELD The present invention relates to classification apparatuses for classifying arthropods, preferably insects, larvae and / or pupae and in particular, but not necessarily, to classifying pupae based on size and thus to classify pupae based on sex. The apparatus and method are particularly, but not necessarily, to be used to classify insect larvae and / or pupae, particularly in mosquitoes.

BACKGROUND The use of sterile insects to control a population of insects, such as that of the mosquito, requires millions of insects to be bred, sterilized and released. In order to release insects on the required scale, the breeding process must be as automated as possible in order to be economical.

For some types of insects there is no need to classify insects based on sex before they are released. However, for other insects it is essential to remove the females, for example, because they transmit the disease or damage crops. Since in females mosquitoes transmit disease, the process of Classification for mosquitoes should be optimized to reduce to the minimum possible level the number of female mosquitoes released while minimizing any loss of male mosquitoes.

Due to the different life cycles of male and female mosquitoes two main stages of classification are usually required for a release program. First, the larvae need to be classified from the pupae and then the male pupae should be classified from the female pupae. This can be achieved on the basis of different sizes of larvae and pupae, for example if male pupae and female pupae are of different sizes (ie on average (average) in the same time period in development). For example, in Ae. aegypti, larvae are smaller, differently and thinner than male pupae. In addition, the pupae tend to float while the larvae are prone to shrink. Male pupae are smaller than female pupae.

In mosquitoes there have been several large-scale breeding programs that have tried to automate the breeding and separation of mosquitoes in their different stages of life. Examples of known devices and methods that have been developed to automate the classification of mosquitoes will now be described with reference to Figures 1 to 3.

An example of a sorting machine that was first described in Focks, D. (1980). "An improved separator for the stages of development, sexes, and species of mosquitoes (Diptera: Culicidae)".

J Med Entomol, 17, pgs. 567-568 is illustrated in Figure 1. The machine includes an aluminum plate that supports two glass plates. The distance between the glass plates is manually adjustable using four control knobs and is set to form a wedge-shaped space that points downward so that when pouring aquatic insect culture between the plates larger specimens larger than plates and smaller specimens are captured inferior to the plates. However, in an experiment it was estimated that for An. Albimanus the classification efficiency of this machine was approximately 85% which means that 15% of the females were present after the classification. There is not enough efficiency that is useful in sterile insect techniques. In addition, the use of the instrument is relatively laborious since the separation needs to be adjusted in use and therefore readjusted for each new batch of specimens to be classified.

Another device is illustrated in Figure 2 and is described in Evans F. D. S. and Evans H. T. in "A simple separator for larvae and pupae of mosquitoes" in Mosquito News 28 (4); 649-650. The device has three tubes, two placed in a horizontal plane with each other and being fixed. The third tube is placed under the two tubes and can be moved to provide an adjustable space for sorting pupal larvae.

In order to classify a sample, the sample is poured between the two cylinders so that it flows over the third cylinder. While the Larger pupae are trapped in the space between the two upper cylinders and the third lower cylinder, the smaller larvae pass through space and are collected. However, as the pupae become trapped between the two cylinders they prevent the passage of the larvae and therefore the device can not be used for high performance classification.

Cold water separation is a technique to separate larvae from pupae. In the separation with cold water larvae and pupae are immobilized in cold water (3-4 ° C). At this temperature the pupae float in the water and the larvae sink so that the pupae and larvae separate automatically. The pupae can then be separated from the larvae, for example, by decanting or using a vacuum selector. In experiments it was found that the separation of cold water causes damage and cold shock to the pupae. Additionally, the technique can be classified only at an efficiency of 80-90% which means that the remaining larvae have to be classified by hand. In addition, its efficiency depends on the species of mosquitoes that are going to be classified.

Finally, the McCray classifier illustrated in Figure 3 was developed to classify pupal larvae. The classifier includes a plurality of slots present in a chamber. Larvae and pupae are poured into the device and a stream of water washes the larvae and pupae over the grooves. The larger female pupae are trapped by the grooves but the washing of male pupae and larvae through the grooves and thus female pupae are separated from the male pupae and larvae. However, as with the device described by Evans and Evans the pupae trapped by the grooves prevent the passage of larvae through the grooves which means that the McCray classifier is not suitable for a high performance classification since the pupae have to be removed from the slots periodically. Additionally, there is no method to remove larvae from male pupae.

Therefore, there is no device that seems to efficiently classify pupal larvae and male pupae of female pupae.

BRIEF DESCRIPTION OF THE INVENTION According to one aspect of the present invention there is provided an apparatus for classifying larvae and / or pupae of arthropods comprising a first and second bar and two parallel bars, each of the parallel bars having a first pivotal connection to the first bar and a second pivotal connection to the second bar, so that the rotation of the parallel bars relative to the first bar changes the distance between adjacent parallel bars. The apparatus is particularly suitable for classifying insect larvae and / or pupae and even more particularly suitable for sorting mosquito larvae and pupae. Thus, it is preferred that the arthropod be an insect, more preferably Diptera, and particularly mosquitoes such as Anopheles species (especially Anopheles gambiae) and / or Aedes (especially Aedes). aegypti).

The apparatus may have a closed structure having two pairs of opposite sides, a pair of opposite sides being formed by the parallel bars and the second pair of opposite sides being formed by the first bar and the second bar, each of the bars being fixed pivotally to each of the bars forming the other pair of opposite sides.

Optionally, there may be a third parallel bar having a first pivotal connection to the first bar and the second pivotal connection to the second bar. In an alternative arrangement a third parallel bar and third and fourth bars are provided, the third and fourth bars have a pivotal joint on both the third parallel bar and one of the two parallel bars.

Each of the first and second bars comprises at least two collapsible portions, the first collapsible portion has a pivotable connection to one of the parallel bars and a pivotable connection to the other collapsible portion, and the second collapsible portion has a pivotable connection to the another of the parallel bars and a pivotai connection to the other collapsible portion.

The apparatus may be provided with one or more intermediate bars and parallel to the first and second bars to form a mesh.

The apparatus preferably includes an element configured to maintain and / or adjust an angle between the first bars and the plurality of parallel bars or distance between the plurality of bars. parallel bars. This element allows the distance between the plurality of bars to be easily changed so that it is optimized to classify different types of pupae and / or larvae according to their size.

The element may be a threaded screw and the sorting apparatus provided with two fasteners having threaded portions complementary to the threaded screw. The two fasteners can be mounted on the first bar and the second bar respectively.

Preferably, the distance between adjacent parallel bars is 0-1.0 mm, 0-1.1 mm, 0-1.2 mm, 0-1.3 mm, 0-1.4 mm or 0-1.5 mm, when the angle between a parallel bar and the first bar is 90 °. It is also preferred that the distance between the adjacent parallel bars be 0-1.1 mm when the angle between a parallel bar and the first bar is 90 °. Even more preferably the distance between adjacent parallel bars is 0.5-2.0 mm, 0.5-3.0 mm, 0.7-2.0 mm, 0.7-3.0 mm and most preferably 0.7-1.1 mm, when the angle between a parallel bar and the first bar is of 90 °.

The bars can be made of one or more wire (including metallic wire, nylon wire or plastic wire); metal bars; plastic bars; and wooden bars. The bars may have any suitable cross section including rectangular, circular, semicircular, triangular or a rectangular cross section with beveled corners.

According to a second aspect of the present invention there is provided an apparatus for classifying larvae of pulps comprising a chamber for receiving pupae and larvae, the chamber comprises a base and a wall wherein the base comprises at least a part of the apparatus of the first aspect of the present invention.

According to a third aspect of the present invention there is provided an apparatus for determining the sex of the pupae comprising a chamber for receiving pupae, the chamber comprises a wall, and an upper part wherein the upper part comprises at least part of the apparatus of the first aspect of the present invention.

The chamber of the second or third aspects of the present invention can be fixed removably to the apparatus of the first aspect of the present invention.

According to a fourth aspect of the present invention there is provided a method for classifying arthropod larvae and pupae comprising the steps of: inserting the apparatus according to any of claims 1 to 14 in water; and place arthropod larvae and pupae to be classified on the apparatus.

The method may include the additional step of raising and lowering the apparatus. This movement of the apparatus promotes the passage of larvae or pupae through the apparatus.

According to a fifth aspect of the present invention there is provided a method for classifying pupae according to size, comprising inserting the first, second or third apparatus aspect of the present invention in water including pupae to be sorted so that pupae of a certain size are moved from the surface of the water. One size of the pupae is therefore separated from another. This can be done within all males, all females or mixed population.

According to a sixth aspect of the present invention there is provided a method for determining the sex of pupae comprising inserting the apparatus of the first, second and third aspects of the present invention into water including pupae from which the sex will be determined in a manner that the pupae are moved from the surface of the water. Therefore one sex of pupae is separated from another, that is to say males of females.

Under some circumstance, the method may include up and down steps, for example as described above, but is generally not preferred for sex determination.

The arthropod can be an insect such as a Diptera. It can be a mosquito such as Anopheles species (especially Anopheles gambiae) and / or Aedes (especially Aedes aegypti).

BRIEF DESCRIPTION OF THE DRAWINGS Figures 1 to 3 illustrate a known apparatus for classifying insects; Figure 4 is an aerial view of the sorting apparatus according to the present invention; 1 o Figure 5 illustrates different configurations of the apparatus for classification of Figure 4; Figure 6 illustrates the sorting apparatus including a chamber for sorting larvae and pupae; Fig. 7 is a flow diagram of a method for using the sorting apparatus of Fig. 6; Figure 8 illustrates a sorting apparatus including a chamber for classifying pupae of different sexes; Figure 9 is a flow chart of a method for using the sorting apparatus of Figure 8; Figure 10 illustrates a sorting apparatus with bars forming a frame that rotatably connect at either end to adjacent parallel bars allowing the frame to be compressed and elongated.

Figure 11 illustrates a sorting apparatus with bars forming a structure so that bars parallel adjacent ones are connected through two bars.

DESCRIPTION The sorting apparatus 10 of the present invention in one embodiment comprises a frame formed by four bars 12 as illustrated in Figure 4. Each bar 12 is rotatably connected at each end to each other of the bars 12 so that the frame forms a shape of quadrilateral with two pairs of sides parallel. Since the bars 12 rotatably connect to each other the frame can have its shape altered so that the angle at the corner of the frame changes while the bars forming opposite sides of the frame re parallel.

The sorting apparatus 10 is provided with a number of intermediate bars 14 extending from one side of the frame to the opposite side of the frame. Each intermediate bar 14 is separated from its adjacent bars by a space, preferably 1.1 mm, when the angle at the corners of the frame is 90 °. Each of the intermediate bars 14 is rotatably connected to the bars 12 forming the frame.

By rotating the frame bars and the intermediate bars, the angle at the intersection of the frame bars can be adjusted by a user. Figure 5 shows how, as the angle between the connected bars becomes greater than 90 °, the distance between adjacent bars decreases (the original position of the bars is shown by the dotted lines). This provides the advantage that the distance between adjacent bars can be calculated by the angle in a connection between bars. Alternatively, the distance between adjacent bars can be measured using any suitable means.

The sorting apparatus 10 is preferably provided with a chamber 20. The chamber comprises four walls 22 which are connected to form a compartment to receive a sample containing larvae and pupae to be sorted. Another side of the The chamber is at least partially formed by the intermediate bars 14 and / or the bars of the frame 12. The chamber may have an open side as illustrated in Figure 6 or be enclosed with an additional wall that is provided on the reing side as illustrated in Figure 8. Examples of cameras 20 are illustrated in Figures 6 and 8.

The sorting apparatus 10 may additionally be provided with suitable means for altering and / or taining the angle between intersection bars. For example, fasteners may be attached to the frame to retain the angle between intersection bars.

Alternatively, as illustrated in Figures 6 and 7, the frame can be provided with a threaded screw arrangement where a threaded screw is used to alter the angle at the corners of the frame. In Figure 6 the sorting apparatus is provided with a support structure 24. The support structure comprises four struts forming a fixed rectangle in a plane parallel to the plane of the sorting device bars. A frame bar is attached to one of the four struts (or forms one of the four struts). The bar forming the opposite side of the frame is provided with a nut configured to receive a threaded screw. Another nut is fixed to a strut so that the threaded screw can pass through both nuts at the same time thereby allowing the rod to be removed relative to the frame by rotation of the screw.

By fixing one side of the frame relative to the support structure and allowing the opposite side of the frame to be moved relative to the support structure by means of a threaded screw the angle and therefore distance between intersection bars can change and fix easily.

In Figure 8 the sorting apparatus is provided with two nuts each in diagonally opposite corners of the frame. The threaded screw is then passed through the nuts. Rotating the screw one way will cause the two diagonally located corners to move closer thereby altering the angle at the corner of the frame and the distance between the rods of the device. Similarly, the rotation of the screw in the other direction will cause the corners located diagonally to move away, altering the angle of the corners of the frame.

As will be understood by one skilled in the art, methods are provided for changing and fixing the positions of the frame bars by way of example only and any other suitable means may be used. Additionally, any type of fastener can be used to connect a threaded screw to the sorting apparatus and / or a support structure.

A method for using the sorting apparatus for sorting pupal larvae will now be described with reference to Figures 6 and 7. In the first step (S1) the sorting apparatus 10, which includes the chamber 20, is placed in a large container (not shown) with enough water to fill approximately half of the chamber 20 illustrated in Figure 6. The larvae and pupae to be sorted can then be placed inside the chamber 20 (S2) and the sorting apparatus 10 raised out of the water (S3). As the device is lifted out of the water the smaller larvae pass through the spaces between the bars 12, 14 of the sorting apparatus inside the container 24. The larger pupae can not pass through the bars and so both remain in the chamber 20. Since the pupae will block the passage of some larvae through the bars, the sorting apparatus 10 is advantageous for repeatedly inserting and removing the water sorting apparatus (S3). The insertion of the water classification apparatus serves to discharge any of the pupae of the spaces between the bars, thereby allowing additional larvae to pass through the spaces when the sorting apparatus is lifted from the water again. This allows a high percentage of the larvae to pass through spaces between the bars. It has been shown that raising the sorting apparatus in and out of the water in the container approximately 10 times classifies approximately 99% of the larvae of the pupae.

Once the sorting apparatus has been inserted into the water a sufficient number of times, the sorting apparatus can be removed from the water (S5) and the larvae can be removed from the water in the container 24 and the pupae can be removed from the chamber.

A method to classify male and female pupae will be described now with reference to Figure 9. This method makes use of the instinct of the pupae to swim towards the surface of the water. In contrast to the modality described above, the camera must be completely enclosed with a base, walls and a side that is formed by the bars of the sorting apparatus as illustrated in Figure 8. In use, the apparatus is oriented so that the camera 20 enter the water in a container before the bars of the apparatus do so.

In this method the male and female pupae to be sorted are placed inside the chamber 20 (S7) and the apparatus is placed in a water container 26 with the upper bars so that it is completely submerged (S8).

As discussed earlier, pupae have an instinct to swim to the surface of the water. This means that the pupae inside the chamber swim up towards the bars 12, 14 of the sorting apparatus 10. The male pupae are smaller than the female pupae and can pass through the spaces between the bars while the female pupae do not they can pass through the bars 12, 14 and remain inside the chamber 20.

Male pupae can then be harvested from the surface of the water and female pupae can be removed from the surface (S.9).

It was estimated that a device with a frame size of 10 * 10 cm can classify 100,000 pupae in one hour. Classification efficiency was proven by classifying more than 3 million pupae male and resulted in an average contamination of 0.03%, contamination here means the proportion of female pupae found in the population of 'male' pupae after classification.

As will be understood by the skilled person, the rods of the apparatus can be made of any suitable material such as nylon wire, plastic wire, metallic wire, wood, plastic, metal. Additionally the bars may have any suitable cross direction. For example, the bars may have a rectangular, circular, semicircular, triangular or rectangular configuration with beveled corner cross section. The bars can have any suitable dimension.

An example of the use of wire in a pupal separation device is provided in a 1972 publication by Sharma et al. ("A device for rapid separation of male and female mosquito pupae"; VP Sharma, RS Patterson, and HR Ford; Bull World Health Organ. 1972: 47 (3); 429-432). It uses nylon wire and is designed to separate pupae from C. p. fatigans, but it is not adjustable and therefore impractical unless it is configured very precisely for each species. An additional problem with fixed wire space is that it caused batch to batch size variation within a species, ie variation in size of one pan or time to another due to a variation in environment (feed, temperature, etc.) or, potentially genetic, which means that adjustment may be required between some lots (even from the same species).

Additionally, additional groups of intermediate bars can be provided between one or more frame pairs. For example, as illustrated in Figure 8 a first group of parallel bars are parallel to a pair of opposite sides and the other group of parallel bars are parallel to the other pair of opposite sides.

The bars forming the frame and / or parallel bars do not need to be linear as illustrated in the Figures but can have any suitable shape. For example, where only one group of parallel bars exists, the sides of the frame not parallel to the bars may have a curved shape. Alternatively, a group of parallel bars can have any suitable shape since the bars are parallel.

The expert will understand that characteristics of the two modalities are easily interchangeable. For example, the adjustment screw described with reference to Figure 6 can also be applied to the sorting apparatus of Figure 8 and vice versa. Similarly the sorting apparatus of Figure 6 can be provided with the additional groups of parallel bars illustrated in Figure 8 and the sorting apparatus of Figure 8 can be provided only with intermediate bars running parallel to a group of opposite sides.

Additionally, the camera is not necessary to implement the classification methods described with reference to Figures 4 and 6. For example, if the sides of the container for liquid receive the As the frame of the sorting apparatus with a distance less than or equal to that between the intermediate bars between the sides of the frame and the container, the sorting apparatus can be used without the camera.

The distance between adjacent intermediate bars or the intermediate bars and the frame can be any suitable distance. An optimum distance of distance between the bars can be determined by the arthropod to be classified. The size of pupae / larvae will differ among several arthropods. For most arthropods, the preferable distance between the bars is 0-3 mm. More preferably, the distance is 0-2.5 mm, 0-2 mm or 0-1.5 mm.

The arthropod could be an insect such as a Diptera. It can be a mosquito such as Anopheles species (especially Anopheles gambiae) and / or Aedes (especially Aedes aegypti). Taking mosquitoes as an example, the distance is preferably 0-1.1 mm. Even more preferably the spacing is 0.7-1.1 mm. Other preferred ranges are mentioned above.

The sorting apparatus may be provided with one or more potholders or any other suitable means to facilitate repeated insertion and removal of water. Alternatively, the sorting apparatus may be connected to means such as a motor for automatically inserting and removing the apparatus from the water.

Additional alternative modes of the classification apparatus are illustrated in Figures 10 and 11. In these figures the frame comprises a group of parallel bars 32 as described previously. In Figure 10 the bars forming a frame are rotatably connected at either end to adjacent parallel bars allowing the frame to be compressed and elongated by rotating the bars forming the frame relative to the parallel bars. In Figure 11 the bars forming the frame are rotatably connected at one end to one of the parallel bars and at the other end to another of the bars forming a frame so that adjacent parallel bars are connected through two bars. This configuration allows a concertina movement to vary the distance between the parallel bars of the frame. The distance between the bars can be adjusted using a threaded screw connected along the distance of an edge formed by the two hinged portions 34 or any other suitable means.

In a preferred embodiment, an apparatus is provided for classifying pupal insect larvae and for determining the sex of pupae based on size (which classifies different sexes), especially in mosquitoes. The apparatus comprises two parallel bars mounted pivotally in a frame so that the distance between the bars is adjustable by angulation of the frame. Insect larvae and pupae can be inserted into a chamber with a side formed by the bar grid and inserted in water to separate the different shapes. The pupae can then be inserted into a chamber covered by a grid of bars and submerged in water. Smaller pupae can swim through the bars and larger pupae remain trapped. In mosquitoes, the smaller pupae tend to be male and the pupae larger females.

Additional references Focks, D. (1980). "An improved separator for the stages of development, sexes, and species of mosquitoes (Diptera: Culicidae)". J Med Entomol, 17, pages 567-568 Bar-Zeev M. and Galun R (1961) A magnetic method for separating pupae from mosquito larvae. 1961. MOSQ. NEWS 21 (3): 225-28 Evans F. D. S. and Evans H. T. 1968 A simple separator for mosquito larvae and pupae. Mosq. News 28 (4): 649-650 Fay R. W., Mccray, E.M. R. and Kilpatrick W. (1963) Mass production of Aedes aegypti from sterilized males. 1963. MOSQ. NEWS 23 (3): 210-14 Fay RW, Morían HB (1959) A mechanical device to separate stages of development, sexes, and mosquito species. Mosq News 19 144-147.

Focks, D. A. (1980) An improved separator for development stages, sexes, and mosquito species (Diptera: culicidae) Journal of Medical Entomology Vol. 17, no. 6: 567-568 Hazard El (1967) Modification of the ice water method to collect pupae of Anopheles and Culex. Mosq News 27 115-116 Lin CS, Georghiou GP (1976) Tolerance of mosquito larvae and pupae under anesthesia with carbon dioxide. Mosq. News 36: 460-461.

M. Ansaki,. R. O. S'ingh, G. D. Brooks and P. R. Malhotra. (1977) A device for separating the larval pupae of Aedes aegypti (dipterans: culicidae). J. MED. ENTOMOL. 14 (2): 241-43 M. Ansaki, K. R. O. Singh, G. D. Brooks, P. R. Malhotra and V. Vaidyanathan. (1975) The development of procedures for the mass rearing of Aedes aegypti (I). WHO / VBC / 75.560: 9P.

McCray EM (1961) A mechanical device for rapid sex determination of Aedes aegypti pupae. J Econ Entomol 54 p819 Ramakrishnan S. P., Krishnamurthy B. S. and Singfa M. N. (1963) A simple technique for rapid separation of mosquito pupae by sudden freezing. 1963. Indian J. Malario), 17 (2/3: 119-21) Vartak P. H. Ramachandran R. Mukherjee S. N. (1989) A device for separating mosquito larvae and pupae. J. COMMUN. DIS. 21 (2): 148-52 Sharma V. P., Patterson, R. S. and Ford H. R. A device for the rapid separation of male and female pupae. Bulletin of the World Health Organization: 47 (3): 429-432 (1972).

Weathersby A. B. (1063) Collect mosquito pupae with cold water. 1963. MOSQ. NEWS 23 (3): 249-51.

Weathersby AB (1963) Collect mosquito pupae with cold water. Mosq News L1-292pdf 23: 249-251

Claims

1. - Apparatus for classifying larvae and / or arthropod pupae comprising a first and second bar and two parallel bars, each of the parallel bars having a first pivotal connection to the first bar and a second pivotal connection to the second bar, so that the rotation of the parallel bars in relation to the first bar changes the distance between adjacent parallel bars.

2. - The apparatus according to claim 1, wherein the apparatus further comprises a closed frame comprising two pairs of opposite sides, a pair of opposite sides being formed by the parallel bars and the second pair of opposite sides being formed by the first bar and the second bar, each of the bars is fixed pivotally to each of the bars that form the other pair of opposite sides.

3. - The apparatus according to claim 1 or claim 2, further comprising a third parallel bar, the third parallel bar has a first pivotal connection to the first bar and a second pivotal connection to the second bar.

4. - The apparatus according to claim 1 or claim 2, further comprising a third parallel bar and third and fourth bars, the third and fourth bars have a pivotal attachment to both of the third parallel bar and one of the two parallel bars.

5. - The apparatus according to claim 1, wherein the first and second bars each comprises at least two collapsible portions, the first hinged portion has a pivotal attachment to one of the parallel bars and a pivotal attachment to another collapsible portion, and the second collapsible portion has a pivotal attachment to the other of the parallel bars and a pivotal attachment to another collapsible portion.

6. - The apparatus according to any of the preceding claims, further comprising one or more bars between and parallel to the first and second bars.

7. - The apparatus according to any of the preceding claims, further comprising an element configured to maintain and / or adjust an angle between the first bars and the plurality of parallel bars or distance between the plurality of parallel bars.

8. - The apparatus according to claim 7, wherein the element comprises a threaded screw and the sorting apparatus is provided with two fasteners having threaded portions complementary to the threaded screw.

9. - The apparatus according to claim 8, wherein the two fasteners are mounted on the first bar and the second bar respectively.

10. - The apparatus according to any of the preceding claims, wherein the distance between adjacent parallel bars is 0-1.1 mm when the angle between a parallel bar and the first bar is 90 °.

11. The apparatus according to any of the preceding claims, wherein the distance between adjacent parallel bars is 0.7-1-1 mm when the angle between a parallel bar and the first bar is 90 °.

12. - The apparatus according to any of the preceding claims, wherein the bars are made of one or more wire (including metallic wire, nylon wire or plastic wire), metal bars, plastic bars and wooden bars.

13. - The apparatus according to any of the preceding claims, wherein the bars have a rectangular, circular, semicircular, triangular or a rectangular section with beveled corners cross section.

14. - The apparatus for classifying pupal larvae, comprising a chamber for receiving pupae and larvae, the chamber comprises a base and a wall, wherein the base comprises at least part of the apparatus according to any of claims 1-13.

15. - The apparatus for determining the sex of pupae, comprising a chamber for receiving pupae, the chamber comprises a base, a wall, and an upper part, wherein the upper part comprises at least part of the apparatus according to any of the claims 1 to 13.

16. - The apparatus according to claim 14 or claim 15, wherein the chamber can be removably attached to the apparatus of claims 1 to 12.

17. - A method for classifying arthropod larvae and pupae comprising the steps of: a) inserting the apparatus according to any of claims 1 to 14 in water; b) place arthropod larvae and pupae that are to be classified on the apparatus.

18. - A method for classifying arthropod larvae and pupae according to claim 17, further comprising the step of: c) raising and lowering the apparatus so that the larvae pass through the apparatus.

19. - A method to classify pupae according to size, comprising the steps of: a) inserting the apparatus according to any of claims 1 to 16 into water including pupae that are to be sized so that the pupae are moved from the surface of the water; and optionally b) raise and lower the appliance so that pupae of a certain size pass through the appliance.

20. - A method for determining the sex of pupae comprising inserting the apparatus according to any of claims 1 to 16 in water including pupae from which the sex will be determined so that the pupae are moved from the surface of the water.

21. - The apparatus or method according to any preceding claim, wherein the arthropod is an insect, such as a Diptera, and particularly mosquitoes such as Anopheles species (especially Anopheles gambiae) and / or Aedes (especially Aedes aegypti).